Question

Well, to be honest it works just for one client, don’t really know why. Also client is receiving everything two or three times. [ I’ve used telnet as a client. When I start another telnet session, it stays, but it doesn’t give any output ].
I will add gui code if needed.

public static void main(String args[]) throws IOException {
    String s;
    initGUI();
    try {
        hostServer = new ServerSocket(port);
        socket = hostServer.accept();
        area.append(" "+socket+" connection\n");
        changeStatusTS(CONNECTED, true);
    } catch (IOException e) {
        cleanUp();
        changeStatusTS(DISCONNECTED, false);
    }
    while (true) {
        try {
            Thread.sleep(10);
        } catch (InterruptedException e) {
            System.out.println(e);
        }
        while(true) {
            multi ml = new multi(socket);
            ml.start();
        }
    }
}

static class multi extends Thread{

    public multi(Socket c) throws IOException {
        socket = c;
    }
    public void run(){
        String s;
        switch (connectionStatus) {
            case CONNECTED:
                try {
                    in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                    out = new PrintWriter(socket.getOutputStream(), true);
                    if (toSend.length() != 0) {
                        out.print(toSend); out.flush();
                        toSend.setLength(0);
                        changeStatusTS(NULL, true);
                    }
                    if (in.ready()) {
                        s = in.readLine();
                       if ((s != null) &&  (s.length() != 0)) {
                          if(s.equals("test")==true){
                          out.print("bazinga"); 
                          out.flush();
                      }

                     if (s.equals(END_CHAT_SESSION)) {
                        changeStatusTS(DISCONNECTING, true);
                     }
                     else {
                        appendToChatBox("INCOMING: " + s + "\n");
                        changeStatusTS(NULL, true);
                     }
                  }
               }
            }
            catch (IOException e) {
               cleanUp();
               changeStatusTS(DISCONNECTED, false);
            }
            break;

         case DISCONNECTING:

            out.print(END_CHAT_SESSION); 
            out.flush();

            cleanUp();
            changeStatusTS(DISCONNECTED, true);
            break;

         default: break; 
         }
    }
    }   
    }

Answer 1

I’ve not looked at the entire code but an immediate problem looks to be that your server is not calling accept() in a loop. I’d change your main to be something like the following:

public static void main(String args[]) throws IOException {
    String s;
    initGUI();
    hostServer = new ServerSocket(port);
    while (true) {
        try {
            // wait for the next client to connect
            socket = hostServer.accept();
        } catch (IOException e) {
            cleanUp();
            changeStatusTS(DISCONNECTED, false);
            break;
        }
        area.append(" " + socket + " connection\n");
        // you probably don't want this or you want this to be per client?
        changeStatusTS(CONNECTED, true);
        // start a multi thread on the accepted socket
        Multi ml = new Multi(socket);
        ml.start();
    }
}

When a client calls connection, the server’s accept() call returns and your code should create a new Multi thread to handle that connection. Then the server should loop around and call accept() again, waiting for the next client to connect.

Hope this helps.